Module 10 Arpin Review

Question 1

basal ganglia nuclei (6)

Answer 1

-caudate
-putamen
-globus pallidus (GPi and GPe)
-subthalamic nucleus
-substantia nigra pars reticulata
-substantia nigra pars compacta

Question 2

what are the input nuclei of basal ganglia

Answer 2

striatum (caudate + putamen) receive input from

-corticostriatal pathways
-brainstem inputs from substantia nigra pars compacta

Question 3

what are the output nuclei of basal ganglia

Answer 3

-globus pallidus internal segment projects to the thalamus (VA/VL complex)
-substantia nigra pars reticulata projects to the superior colliculus

Question 4

medium spiny neurons

Answer 4

-GABAergic neurons in the striatum
-receives glutamatergic inputs from cortical neurons
-receives input from dopaminergic neurons
-axons project to globus pallidus

Question 5

which pathway facilitates movements

Answer 5

direct basal ganglia pathway

Question 6

direct basal ganglia pathway

Answer 6

-at rest, the GPi tonically inhibits the thamalus (which excites the frontal cortex)
-the striatum transiently inhibits the globus pallidus, which causes disinhibition of the thalamus (which excites the neurons in the frontal cortex)

Question 7

eye movements

Answer 7

-the substantia nigra pars reticulata tonically inhibits the superior colliculus
-when the caudate is transiently activated, the inhibition on the superior colliculus is reduced, causing activation of the gaze centers

Question 8

eye movements are acheived via indirect/direct basal ganglia pathway

Answer 8

direct basal ganglia pathway

Question 9

which pathway inhibits movements

Answer 9

indirect basal ganglia pathway

Question 10

indirect basal ganglia pathway

Answer 10

-involves the subthalamic nucleus, which acts to increase the inhibitory output from the globus pallidus internal segment (GPi)
-the subthalamic nucleus becomes activated when the GPe is inhibited by neurons in the striatum

Question 11

how do the direct and indirect pathways work

Answer 11

work together to facilitate a specific motor output, while suppressing other competing motor programs

Question 12

which neurotransmitter is input to the striatum

Answer 12

dopamine

Question 13

dopmine input to the striatum is provided by

Answer 13

neurons in the substantia nigra pars compacta

Question 14

what does dopamine excite

Answer 14

excites medium spiny neurons in the GPi that have D1 dopamine receptors

Question 15

what does dopamine inhibit

Answer 15

inhibits medium spiny neurons in the GPe that have D2 dopamine receptors

Question 16

Parkinson’s disease

Answer 16

diminished dopamine inputs from the substantia nigra pars compacta
-more tonic inhibition from GPi on thalamus
-hypokinetic movement disorder

Question 17

Huntington’s disease

Answer 17

degeneration of medium spiny neurons in striatum that project to GPe
-increases tonic inhibition of GPe on the subthalamic nucleus
-the indirect pathway becomes less effective at opposing the effects of the direct pathway
-hyperkinetic movement disorder